Employee Benefit Plans: Projected Benefit Plan Payments (Details) (USD $) In Thousands, unless otherwise specified	Dec. 31, 2014
Pension Plans, Defined Benefit [Member]
Defined Benefit Plans and Other Postretirement Benefit Plans Table Text Block [Line Items]
Defined Benefit Plan, Expected Future Benefit Payments in Year One	$ 14,712
Defined Benefit Plan, Expected Future Benefit Payments in Year Two	15,629
Defined Benefit Plan, Expected Future Benefit Payments in Year Three	16,561
Defined Benefit Plan, Expected Future Benefit Payments in Year Four	17,556
Defined Benefit Plan, Expected Future Benefit Payments in Year Five	18,741
Defined Benefit Plan, Expected Future Benefit Payments in Five Fiscal Years Thereafter	109,147
Supplemental Employee Retirement Plans, Defined Benefit [Member]
Defined Benefit Plans and Other Postretirement Benefit Plans Table Text Block [Line Items]
Defined Benefit Plan, Expected Future Benefit Payments in Year One	1,486
Defined Benefit Plan, Expected Future Benefit Payments in Year Two	1,573
Defined Benefit Plan, Expected Future Benefit Payments in Year Three	1,627
Defined Benefit Plan, Expected Future Benefit Payments in Year Four	1,670
Defined Benefit Plan, Expected Future Benefit Payments in Year Five	1,780
Defined Benefit Plan, Expected Future Benefit Payments in Five Fiscal Years Thereafter	8,901
Other Postretirement Benefit Plans, Defined Benefit [Member]
Defined Benefit Plans and Other Postretirement Benefit Plans Table Text Block [Line Items]
Defined Benefit Plan, Expected Future Benefit Payments in Year One	3,921
Defined Benefit Plan, Expected Future Benefit Payments in Year Two	4,011
Defined Benefit Plan, Expected Future Benefit Payments in Year Three	4,057
Defined Benefit Plan, Expected Future Benefit Payments in Year Four	4,169
Defined Benefit Plan, Expected Future Benefit Payments in Year Five	4,236
Defined Benefit Plan, Expected Future Benefit Payments in Five Fiscal Years Thereafter	$ 19,877

Amount of benefits from a defined benefit plan expected to be paid in the five fiscal years after the fifth fiscal year following the latest fiscal year. Excludes interim and annual periods when interim periods are reported on a rolling approach, from latest balance sheet date.

Reference 1: http://www.xbrl.org/2003/role/presentationRef

-Publisher FASB

-Name Accounting Standards Codification

-Topic 715

-SubTopic 20

-Section 50

-Paragraph 1

-Subparagraph (f)

-URI http://asc.fasb.org/extlink&oid=35743120&loc=d3e1928-114920

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- Definition

Amount of benefits from a defined benefit plan expected to be paid in the next fiscal year following the latest fiscal year. Excludes interim and annual periods when interim periods are reported on a rolling approach, from latest balance sheet date.

+ References

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- Definition

Amount of benefits from a defined benefit plan expected to be paid in the fifth fiscal year following the latest fiscal year. Excludes interim and annual periods when interim periods are reported on a rolling approach, from latest balance sheet date.

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- Definition

Amount of benefits from a defined benefit plan expected to be paid in the fourth fiscal year following the latest fiscal year. Excludes interim and annual periods when interim periods are reported on a rolling approach, from latest balance sheet date.

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- Definition

Amount of benefits from a defined benefit plan expected to be paid in the third fiscal year following the latest fiscal year. Excludes interim and annual periods when interim periods are reported on a rolling approach, from latest balance sheet date.

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- Definition

Amount of benefits from a defined benefit plan expected to be paid in the second fiscal year following the latest fiscal year. Excludes interim and annual periods when interim periods are reported on a rolling approach, from latest balance sheet date.

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